The Study Of Transformer Electric Force Caused By Magnetically Inrush Current

Power transformers are an important part of every transmission equipment,Power transformers are not only responsible for converting other energy into electrical energy,but also responsible for distributing and delivering the electricity according to a certain proportion.In order to ensure the safe and reliable operation of the entire power system,the transformer must not in a fault.Once the transformer internal circuit,first of all to protect is the internal winding,because the transformer short-circuit occurs,the transformer generated enormous short-circuit current will lead to damage to the winding,affecting the normal operation of the transformer.Transformer coil mechanical strength is insufficient,can not withstand the sudden short-circuit current impact is one of the main causes of transformer failure.Therefore,to avoid the occurrence of short circuit failure and improve the internal structure of the transformer compression capacity has become the most important task.In order to improve the ability of the windings in the transformer to withstand the short-circuit current impact,the short-circuit mechanical force of the composite wire with different turns insulation thickness,ordinary transposition wire and self-adhesive transposition wire is studied and analyzed.Firstly,the reason and the form of the mechanical force of the short circuit of the transformer coil are analyzed.The theoretical calculation of the axial short-circuit mechanical force of the coil is carried out by the theoretical knowledge related to the electromagnetic field.Secondly,the axial pressure test of the transformer coil is carried out to simulate the axial compression state of the coil under short circuit conditions and undercurrent surge conditions,thus obtaining the experimental value and the failure form of the compressive stress of the transformer coil.Finally,the finite element analysis method is used to simulate the axial mechanical force of the transformer coil,and the size and position of the maximum stress of the transformer coil in the axial compression are obtained.By comparing the theoretical calculation,the experimental data and the results of the simulation analysis,the calculation method of the compressive stress of the insulated wire is optimized,and an insulation thickness coefficient is introduced to ensure that the transformer is in the short circuit condition and the excitation current condition.The safety of the conductor insulation in the axial compression state.Not only can effectively reduce the transformer circuit fault problems,but also greatly improve the transformer short circuit resistance,enhance the safety of transformer operation,reduce the short circuit failure caused by the adverse effects of the transformer.